Rotary core-cutting drill for wells.



J. L. CAMERON.

ROTARY com CUTTING umu TUR WELLS. APPLICATION FILED JULY 13, |918. l95%10 Patented Apr. 22, 1919.

JARRETT L. CAMERON,

0F EDGERLY, LOUISIANA, ASSIGNOR 0F ONE-HALF 'IO` EVANGELINE IRON WORKSLTD., 0F VINTON, LOUISIANA, A CORPORATION OF LOUISIANA.

ROTARY CORE-CUTTING DRILL FOR WELLS.

Specification of Letters Patent.

Patented Apr. 22, i919.

Application led July 13, 1918. Serial No. 244,715.

To all whom it may concern:

Be it known that I, J ARRETT L. CAMERON, a citizen of the United States,residing at Edgerly, in the county of Calcasieu and State of Louisiana,have invented certain new and useful Improvements in Rotary Core-CuttingDrills for Wells, of which the following is a specification` referencebeing had to the accompanying drawings. a

This invention relates to the art of well drilling and particularly to arotary milling tool for use in this art.

lVith wells being driven by the hydraulic rotary process, 'or later whenproducing oil, tools or pipe may become lostl in the well and cannot berecovered thereby obstructing the well tube a-ndpractically ruining thevalue of the Well. In numbers of such instances, a Well may be workedover by drilling a long slanting hole out through the well casing aboveSuch obstructions and making a new hole down to the oil bearing sands,which operation is commonly called side tracking a well. This operationis begun by'inserting, in the Well a side tracking guide which isusually a solid iron casting having a diameter nearly that of the wellcasing at its lower end and having a long upwardly sloping face,concaved somewhat tothe circle of the well casing. `This guide isinserted in thc` wel] to the depth at which the new hole is tobe begunand the hole made by a form of rotating milling cutter attached to thedrill pipe, rotatal'ile, by means of the -connected sections of drillpipe reaching to machinery for this purpose at the top ofthe well. Thethin wall of the well casing -cutting more readily .than the solid ironguide, the cutting tool follows down the sloping taper of the guide.away from the axial center of the well. cutting away the wall of thewell casing tol the same sloping slant as "the, inserted giiide, whichoperation when completed allows of the further deepening of the well outthrough this hole to proceed by the usual method of drilling.

Heretofore, the openings in the casing of the well have been made with.practically solid steel tools having longitudinally extendingperipheral teeth, or tools having a cylindrical body `portion providedwith peripheral teeth but having their lower endsmpering centrally andhaving peripheral to cut and grind rlway all of the wall of the wellcasing for` the full length of cutting but this method yof operationpresented difficulties. Thus the square ended tool lirst referred to hasa tendency to cut into the guide casting and thus there was dihculty ingetting a long sloping hole through the well casing, which is absolutelynecessary for further drilling. That form of tool having a taperinglower end, while not open to the objection of cutting into the guidecasting, has a tendency to run clear outside of the well casing as soonas the center of the cutting tool has passed the casing, thus notcompleting the tapering hole for the full length of the guide. Thistended to bend the drill pipe, that is the tubular shank to which thedrill is attached and often cause the drill pipe tobe broken ott' andthe tool lost, and at the best the opening in the well casing was not ofsuch form as would permit the ready voperation of tools for furtherdeepening the well.

The general object of this invention is to provide a milling tool forthe purpose before described, which is so constructed that `it will outa relatively long elliptical face y pleted so that this piece or tongueof metal,

so long as it remains joined at its lower end to the well casing, actsin a manner as a guide so that the tool follows down as near the centerof the core as possible until this core or tongue cut from the wellcasing is cut off at the eXtreme lower end of the taper on the guide.

A further object is to provide a tool of this character so constructedthat instead of cutting away all of the well casing with which the toolcomes in contact, the tool will saw narrow slots down on each side ofthe core or tongue, thus making the tool operate ymuch more quickly thanif the tool was solid and cut. through all of the material forming thatportion of the wall acted upon by the tool.

The further Objectis to improve upon the form of the milling tool byproviding a milling tool made in separate sections and which will cutout a core of the well casing to be removed.

A further object of my invention is to provide a milling tool made inseparate seclso tions, any section of4v which when worn out may bereplaced by a duplicate sectlon.

A further object is to provide a milling tool of the above characterrequiring aminimum quant-ity of high tempered cutting steel toaccomplish the results required. A further object is to provide amilling tool which will core out a maximum dimension' of the well casingto be out away and provide a means of retaining this oored'center withinthe tool and the adjacent section of drill pipe when it is removed fromthe well.

Other objects will appear in the course of the following description.

My invention is illustrated in the accompanying drawings, wherein:

Figure 1 is a side elevation partly in section of my improved millingtool;

Fig. 2 is a sectional view of a -well and casing, and the milling toolas used;

Fig. 3 is a plan viewof the core retaining ring; and

Fig. 4 is a section on the line 4-4 of Fig. 3.

Referring to these figures, it will be seen that my improved toolcomprises an annular or tubular body 10, interiorly screw-threaded atits upper end for direct connection to the drill pipe 19 and interiorlyscrew-threaded at its lower end'for engagement with the screw-threadedbody 11 of the drill head-13.

lThe annular body 10 is recessed rearward of the cutting head for theinsertion of the core retaining ring 16, this recess being of such depthas to permit of a free rotative movement of the core retainingringwithin the body, but preventing more than a very slight longitudinalmovement of the core retaining ring when the cutting head is inposition.

The cutting head is reduced to form the shank portion 11, this shankportion being exteriorly screw-threaded for engagement with the lowerend of the section 10 and the cutting head is provided with a pluralityof outer cutting edges 14 at dii'erent angles so disposed as to maintaina continuous cutting engagement with the inner circle of a wel casing asthe tool progresses down the sloping taper of an inserted guide A, asshown in Fig. 1.

The greatest exterior diameter of the outside edges of the cutting head13 is equal to the diameter of the new hole to be cut out through thewell casing and larger than'the outside diameter of the annular body 10,as shown in the drawings, to thereby cut away la free clearance for thebody of the tool.

The interior diameter of the annular body 10 is slightly less than thatof the drill pi e 19 and the cutting head has also a slight y lessinterior diameter. The cutting head 13, in order that it may cut awaythe wall wof the well casing, must of necessity be made of high gradecutting steel, and by constructing the tool in lccordance with Fig. 2,it is obvious that only a minimum quantity of such steel is-required.-

The core retaining ring 16 is of the same annular formation, is looselydisposed within the recess in the body of the tool, and is held withinthis recess by the connected end of the cutting head when it is inposition. The inward face of this retaining ring 16 is beveled inwardand rearward to a sharp edge, and beveled to a suiiciently smallerdiameter as to maintain a frictional grip on the cored center of thewell casing. This core retaining ring 16 is further provided with anumber of longitudinally extending grooves 17 of alesser angle than thebeveled face, these grooves being designed to facilitate `the inwardpassage of rough edges of the cored center of the well casing. It willbe seen that by -providing this loosely rotatable retaining ring 16, thecored center is frictionally gripped by this ring and does not tend torotate with the tool, whereas the cored center would otherwise tend toblnd and rotate with the tool and be broken o 1 As before stated, thistool is constructed for the purpose of cutting a long sloping hole outthrough the side of the well casing. With a well casing of 6 inches indiameter this sloping hole is from '12 to l5 feet long to allow forfurther deepening of the welll out through the hole without bending thedrill pipe to such 4an extent that it will be vbroken off. It will thusbe seen that it is necessary that the lower end. of the drill shall haveteeth projecting beyond the body upon which the'cutting head is mountedso as to gradually cut in to theside of the well casing with the drillat a slight angle. Furthermore, it is necessary, under thesecircumstances, to cut out a core at an angle to the -vertical center ofthe well and bring out a concave shaped elongated piece of the wellcasing as a core. It is for this reason that I provide the solid coreretaining ring 16 'beveled to a slightly smaller diameter than theinside of the cutting head, this ring being freely rotatable but heldfrom longitudinal movement within the body. lAs the tool is operated tocut downward through the well casing and at an angle to the axisthereof, the tongue so cut out of the well casing will gradually moveupward into the interior of the drill and will be engaged by the'ring16. The ring will, therefore, be held fromrotation and will jam on andbind on the core, bending this concave core slightly as it is forceddown thereon. Inasmuch as the retaining ring 16 is smaller in insidediameter than the inside diameter of the body 10,. and is freelyrotatable, it remains stationary while the drill rotates sol and it alsofunctions to hold thel core from any great frictional contact with theinside of the body which mighttend to break the core off. The ring isbeveled inwardly and upwardly and held from any longitudinal movement sothat it may be forced over and maintain a frictional grip on the coredcenter, as the hole is being made. While not requiring a great force toslip the concave shaped elongated core forward by the tongue cut out ofthe well casing upwardly. through this bevel retaining ring, a very muchgreater force will be required to pull it outward against the sharpupper edgeof the ring.

In summing up it will be observed that I have designed a tool that willbring out as a cored center a maximum dimension of the well casing to becut away and designed a tool in which a minimum amount of high gradecutting steel will accomplish the -result requiredo lt is further to beobserved that until the sliver or tongue cut from the well casing andwhich forms the core is entirely cut away at its lower end, this' sliveror tongue forms a guide for the drill which prevents the drill fromsuddenly moving out beyond the well casing and running clear outside ofthe well casing. This sliver or tongue, therefore, acts' as a guide forthe tool and the tool follows as near to the center of the core aspossible until it is forced to cut olf the core at the extreme lower endof the taper. This tool when withdrawn, therefore, leaves the wellcasing with a long, relatively narrow opening in its side wall throughwhich further drilling can proceed without difficulty, and thus duringthe greater portion of its movement, the drill is cutting merely twoslits in the metal of the well casing of approximately a width of Havingthus described my invention, what l claim is:

1. A tool of the character described comprising an annular body,.including a cutting head, a freely rotatable non-expansible coreretaining ring disposed within the body and held from longitudinalmovement relative to the body, the ring having an inwardly andrearwardly beveled face, beveled to a slightly smaller circle than theinterior diameter of the cutting head and having longitudinallyextending grooves.

.2. A tool of the character described comprising an annular body, a coreretaining ring disposed within the body-rotatable relative thereto butheld from longitudinal movement relative thereto, and a cylindricalcitting head detachably carried by the body and having a plurality ofradially extending cutting teeth projecting laterally beyond the bodyand having cutting edges extending parallel to the body and thendownward and inward toward the longitudinal axis of the body, theexterior diameter of the cutting teeth being greater than that of thebody, the lower end 'of the body being formed with radially disposedteeth.

3. A tool of the character described comprising a hollow body having itsinterior diameter increased at one end and screwthreaded for' a portionof its length, there being a shoulder defining the .inner end of thisportion of the body, an annular cutting head having cuttin teeth at oneend and exteriorly screwreaded for engagement with the interiorscrew-threads of the body, the ,inner end of the cutter head beingspaced from said shoulder when the cutter head is in place, and acoreengaging ring disposed between the shoulder and the inner end of thecutter head and having free rotation therein but held from longitudinalmovement, thering having an interior diameter slightly less than theinterior diameter of the body and being beveled centrally and away fromthe cutter head.`

4. ln combination/with a well drill pi-pe, a rotary milling tool forside tracking wells comprising an annular body having a cylindricalcutting head larger in diameter than the body, the cutting head beingformed with radially projecting teeth extending parallel to the axis ofthe body, downwardly and centrally extending cutting teeth, and thelower end of the body being formed with. radially disposed cuttingteeth.

5. A rotary milling tool for side tracking wells including a bodyannular throughout its entire extent, the lower end of the body havingan enlarged head and formed to provide radial teeth extending parallelto the axis of the body, downwardly and inwardly extending teeth, radial.teeth at the lower end of the body, and a core retaining ring disposedwithin the body and having free rotation therein -an'd held fromlongitudinal movement. f

ln testimony whereof l hereunto affix my Asi, ;nature in the presence oftwo`witnesses.

JARRETT L. CAMERON. `llVitnesses:

ALSER WEHRn, FRED SMITH.

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